Although stimulus-response compatibility and response precuing effects are of major concern in the area of perceptual-motor performance, aging research on these effects has been sporadic and has produced inconsistent findings. The existing aging research is dated and does not reflect the significant theoretical advances on these topics that have occurred in recent years. Some studies of spatial compatibility effects show larger effects for older than younger adults, whereas others do not. Of the studies conducted on response precuing effects, the results obtained for precuing discrete keypress responses are discrepant with those for precuing aimed movement responses: The former suggest that older adults have difficulty preparing two responses on different hands, but the latter show that older adults are able to benefit from all types of precues evaluated. The goal of this pilot project is to initiate a systematic investigation of the influence of aging on response selection in basic perceptual-motor tasks. Four experiments are included as part of this pilot project. For all experiments, performance of college-age adults (18-25 years) will be compared to that of older adults (55-70 years). Experiments 1 and 2 focus on the effects of stimulus response compatibility, examining the role of stimulus and response modalities. Experiments 3 and 4 focus on response precuing effects, examining whether the elderly are less able to prepare responses on the same hand and whether any differences in precuing relative to the young adults reflect simply the need for more preparation time. The participants recruited for the project will be diverse in terms of gender, racial, and ethnic composition. The results from these experiments will resolve fundamental issues regarding aging and response selection, and will provide a solid foundation for the development of a more extensive research program that evaluates a wide range of response selection issues pertaining to aging. This research will also provide information that can be applied to the development of design guidelines for maximizing response speed and accuracy of elderly adults in perceptual-motor tasks. These guidelines will lead to development of products and environments that allow elderly adults to remain more independent and to engage safely in more activities in their daily lives.